Shale gas well wellhead device based on operation under pressure

Abstract

The invention discloses a shale gas well wellhead device based on operation under pressure, and belongs to the technical field of shale gas exploitation. The shale gas well wellhead device based on the operation under pressure comprises a wellhead feeder, the lower end of the wellhead feeder is fixedly connected with a main control rubber valve, a threaded flange is arranged at the upper end of the wellhead feeder, the threaded flange is in threaded connection with the wellhead feeder, the lower end of the main control rubber valve is fixedly connected with a transfer four-way pipe, the left end and the right end of transfer four-way pipe are fixedly connected with a side manual gate valve, and an outer sleeve is arranged on the lower side of the transfer four-way pipe. The shale gas wellhead device is improved, and the shale gas wellhead device is enabled to be suitable for shale gas mining work of the operation under pressure, and a sealing mechanism of the wellhead device can seal the shale gas on the lower side of a mining device well. With the increase of the internal pressure of a plate-shaped shale layer, the sealing effect of the shale gas is enhanced, the leakage of shalegas is reduced, and the shale gas resource waste and destruction of the external environment are reduced.

Description

technical field [0001] The invention relates to the technical field of shale gas exploitation, and more specifically, relates to a wellhead device of a shale gas well based on pressure operation. Background technique [0002] Shale gas refers to unconventional natural gas that occurs in organic-rich shale-dominated reservoir rock series. It is continuously generated biochemical gas, thermogenic gas or a mixture of both, and can exist in natural fractures in a free state. It exists in the surface of kerogen and clay particles in an adsorbed state, and a very small amount is stored in kerogen and asphaltene in a dissolved state. The proportion of free gas is generally 20% to 85%. The formation and enrichment of shale gas has its own unique characteristics, and it is often distributed in thick and widely distributed shale source rock formations in the basin. Compared with conventional natural gas, the development of shale gas has the advantages of long mining life and long pro...

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Problems solved by technology

[0004] Clean and low-carbon shale gas can increase the supply of natural gas, optimize the energy structure, and ease the pressure of emission reduction, which leads to high pressure and difficulty in exploitation. However, the structure of the existing shale gas wellhead device has a large torque and is inconvenient to open. The sealing performance of the whole device is not good and the service life is short, which seriously restricts the development of China's shale gas energy. There are two connected first gate valves and threaded flanges; screw plugs are provided on the threaded flanges; hangers are installed in the oil pipe head spool; jacking wires are provided at the upper end of the tubing head spool; the end of the jacking wires is connected to the hanger , used to prevent the hanger from moving; the upper end of the oil pipe head cross is connected to the second gate valve; the upper end of the second gate valve is connected to the hydraulic gate valve; the hydraulic gate valve is a ball screw valve; the hydraulic gate valve is connected to the third gate valve through a variable diameter flange The third gate valve is connected with the lower end of the four-way; the left and right ends of the four-way are respectively connected with the third gate valve and the shut-off valve; the upper end of the four-way is connected with the fourth gate valve; the upper end of the fourth gate valve is connected with the angle globe valve and the pressure gauge buffer in turn Connected with the pressure gauge, the shale gas wellhead device of the utility model has the characteristics of convenient operation, small torque force, flexible opening, reliable sealing performance, and low noise, which has greatly promoted the development of shale gas energy in China

[0005] Although the above-mentioned technical solution can reduce the torque of the valve to make it open more flexibly, and at the same time, the sealing performance is reliable and the noise is low, but when it is applied to the shale gas exploitation with pressure, the sealing performance of the shale gas wellhead device is difficult. As the service life increases, the flanges inside some shale gas wellhead devices cannot continue to seal the shale gas on the lower side of the production device well due to internal high-pressure oil pressure gas corrosion. After filling fillers are injected into the slab shale layer, the internal pressure of the slab shale layer increases, and the original shale gas wellhead device cannot adapt to the new underground pressure difference, resulting in part of the shale gas leaking from the wellhead device, causing both The waste of shale gas resources also causes damage to the external environment

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